This invention relates to improved internal combustion engines More particularly, it relates to internal combustion engines having a crankless drive mechanism for converting reciprocal rectilinear movement into rotary movement.
A conventional commercially available internal combustion engine utilizes a crank shaft to transform a reciprocating piston motion into a rotary motion. As the piston moves within its cylinder in response to expanding gases of combustion, rotary motion is imparted to the crank shaft through a connecting rod. One end of the connecting rod is affixed to a wrist pin pivotally secured to the piston, while the other end is rotatably journaled about an offset throw of the crank shaft. When multiple cylinder arrangements are desired, the crank shaft is extended to include an additional offset throw for each piston connecting rod.
As the piston transmits force created by the combustion of fuel to the crank shaft by way of the connecting rod, the angularity of the connecting rod causes a considerable side thrust to be exerted by the piston on the walls of the cylinder. This angular thrust is generally absorbed by a skirt portion of the piston; that is, the section below the piston rings. This side thrust or angular force absorbs a portion of the linear energy and contributes to the inefficiency of the conversion of the linear movement of the piston into the rotary movement of the crank shaft.
In a conventional internal combustion engine, the crank shaft is supported by main bearings, and at the end of the crank throw, a crank pin holds the connecting rod. In order to compensate for energy lost to angular forces, the piston rod is lengthened and the crank throw is made longer than the radius of the cylinder bore. Thus, additional space must be allowed to accommodate the crank throw. In addition, to avoid a downward thrust of the piston while the piston is at the upper limit of the stroke (top dead center), the crank shaft or crank pin may be offset from the longitudinal center of the cylinder, or alternatively a timing mechanism may be employed to delay spark ignition in the combustion chamber. These factors further contribute to increased size of commercially available internal combustion engines.
Furthermore, the timing of fuel inlet and spark ignition is crucial in commercial spark ignited internal combustion engines Auto ignition or knocking may occur as a result of poor timing or variances in the quality of fuel. Attempts have been made to solve these problems by employing timing mechanisms to allow high pressures in the combustion chamber to be available when the crank throw is approximately 90 degrees into the power stroke. These timing mechanisms, however, have been unsuccessful.
In an attempt to improve upon the inefficiency of the conventional commercially available crank shaft engine, U.S. Pat. Nos. 3,356,080 and 3,370,510 disclose internal combustion engines which employ wobble plates to convert linear piston reciprocation into rotary movement. In such an engine, a number of cylinder piston units are disposed around a crank shaft with the lines of reciprocation of the pistons parallel to the axis of the crank shaft. Connecting rocker arms are disposed in general planes radial of the axis of the crank shaft Each rocker arm is engaged at its radially inner end with an inclined crank pin and at its radially outer end with a reciprocating part of one of the cylinder piston units
Other internal combustion engines, having crankless drive mechanisms, have been suggested for converting the reciprocating rectilinear movement of pistons into rotary movement For example, U.S. Pat. Nos. 3,135,166, 3,901,093 and 4,497,284 disclose a swash plate in place of the crank shaft to directly convert the reciprocation of pistons to rotary movement In a swash plate, an output shaft is driven by a means of connecting rods which have simple clevis type attachments at both ends.
Another approach proposed by the prior art for replacing the conventional crank shaft is the cam internal combustion engine. For example, in U.S. Pat. No. 2,274,097, reciprocating rectilinear pistons impart rotation to a cam plate through wrist pin runners attached to the piston rod which reciprocates in guide grooves.
U.S. Pat. No. 2,337,330 discloses a crankless internal combustion engine containing a driving pinion and two gear wheels. Two power cylinders positioned on either side of a drive shaft contain a reciprocating piston having an attached rack. The teeth of the opposed racks mesh with the opposite sides of a pinion such that, as the pistons reciprocate, a drive shaft to which the pinion is attached alternately rotates in opposite directions. A driving pinion is attached to one end of the shaft and also rotates in opposite directions with the driving shaft. The alternate rotation is translated into a constant rotation in one direction by two segmental gear wheels which mesh with the driving pinion. Each gear wheel contains teeth projecting around a portion of its periphery so as to form a segment while the remaining portion of the periphery is blank. A mechanism is provided for disengaging the driving pinion from its mesh with one of the segments when the drive of the pinion to the other segment commences.
U.S. Pat. No. 4,465,042 discloses a crankless internal combustion engine wherein a connecting rod moves along in an essentially vertical line within a cam track. During the power stroke, the piston applies force to the rod which extends downwardly from the piston. The lower end of the rod is guided along a closed, curvilinear, vertically extending path as the piston reciprocates. A power output shaft is rotatably supported adjacent to and outside the cam track. A drive member is secured to the power output shaft and has a peripheral portion extending along the cam track As the lower end of the rod moves along the cam track, it carries a force transmitting member which engages the drive member transferring power to the output shaft.
The prior art crankless internal combustion engines contain multiple moving parts which increase the amount of energy lost to frictional forces and wear and tear. To the best knowledge of the inventors of the present invention, these prior art crankless engines have therefore not been commercially successful. Thus, the conventional commercially available reciprocating piston engines are inefficient energy transfer devices because of their loss of energy to angular forces, or because of energy lost to frictional forces and wear and tear.
There is therefore a long felt but still unsatisfied need for a commercially feasible internal combustion engine which converts a higher proportion of the linear energy of the piston into rotation energy than the conventional crank drive engines.
Accordingly, it is an object of the present invention to provide an internal combustion engine for efficiently converting the reciprocating movement of a piston into rotational movement
A further object of the present invention is to provide an internal combustion engine which converts reciprocal movement into rotary movement while employing a minimum number of moving parts
Another object of the present invention is to provide an internal combustion engine which is smaller in size and yet converts reciprocal movement of a piston into rotary movement more efficiently than commercially available engines.
A still further object of the present invention is to provide an internal combustion engine which reduces the amount of energy lost to angular and frictional forces when reciprocal linear energy is converted into rotational energy.
An additional object of the present invention is to provide an internal combustion engine which can burn a low quality fuel and yet efficiently convert the reciprocating movement of a piston into rotary movement.
Yet another object of the present invention is to provide an internal combustion engine which can experience autoignition, knocking, or detonation and still efficiently convert the reciprocating movement of a piston into rotary movement.
A further object of the present invention is to provide an internal combustion engine having parts which can be designed for the most efficient operation depending on the type or quality of fuel which is available for consumption.
A still further object of the present invention is to provide an internal combustion engine which is substantially more tolerable of imprecise timing of the burning of the fuel mixture during the power stroke of the piston than the conventional engines.
Still another object of the present invention is to provide an internal combustion engine which eliminates the need for costly and pollutive fuel additives.
A further object of the present invention is to provide a crankless internal combustion engine wherein the arm component is maintained at a maximum substantially through conversion of rectilinear movement of the piston into rotary movement.
An additional object of the present invention is to provide a crankless internal combustion engine which will burn fast burning fuels without the employment of fuel additives such as those used in conventional crank shaft engines to control or delay combustion in the combustion chamber.
A further object of this invention is to provide an internal combustion engine requiring less manufacturing costs, less repair and maintenance costs, while giving better overall performance and increased fuel economy than conventional commercially available internal combustion engines.
These and other objects of the present invention will become more apparent to those skilled in the art in view of the following disclosure.